The Homeowner's Playbook for Wood-Destroying Pest Damage

4 categories cover almost all of it. Subterranean and drywood termites (the biggest single source, billions in annual U.S. damage and treatment costs), carpenter ants (moisture-driven, common in northern and Pacific Northwest regions), carpenter bees (exterior cosmetic and structural damage to untreated wood), and wood-boring beetles (powderpost beetles, old house borers).

Subterranean termites alone account for the bulk of the cost because they're present in 49 of 50 states and active year-round in southern climates. The damage is usually 5 to 7 years old by the time it shows on the surface, which is why annual pro inspections matter so much in high-risk regions.

Standard HO-3 policies almost always exclude termite damage outright. The exclusions are explicit, and the carrier will point to them. The narrow exception is sudden, accidental, and unforeseen events tied to a covered peril (a falling tree opening the envelope to fresh termite entry that was previously absent, for example).

Plan to pay out of pocket and build the cost into annual home maintenance budgeting. Document everything anyway. Some policies offer riders, transferable termite bonds with damage coverage may apply, and resale disclosure laws in most states require disclosure of known wood-destroying pest history regardless of who paid for the repair.

Always treatment first, then assessment, then repair. Repairing wood while the colony is still active just gives the colony fresh material to consume. The treatment phase runs 2 to 4 weeks. The 30 to 60 day wait for confirmed inactivity follows. Assessment with an engineer for any structural damage. Repair last.

Skipping the wait is the most common DIY mistake. Homeowners want the visible damage gone fast and close up the wall before confirming colony death. The next round of damage happens behind the new drywall where you can't see it for another 5 to 7 years.

Carpenter bees drill perfectly round 1/2 inch entry holes into untreated exterior wood (fascia, eaves, deck rails, fence posts) and tunnel along the grain to lay eggs. Damage compounds year after year because females return to the same site. The signature is round entry holes plus yellowish staining below from frass and droppings.

Carpenter ants don't drill round holes. They excavate galleries inside damp or damaged wood for nesting and produce kick-out slits and sawdust-textured frass with insect parts mixed in. Carpenter bee damage is almost always exterior on visible trim. Carpenter ant damage is usually interior or hidden inside wet structural wood.

Any time the damage involves load-bearing members. Studs in load paths, joists, sill plates, headers, beams, and rim joists. An engineer assesses whether the remaining cross-section is adequate, whether sistering is appropriate, or whether replacement is necessary. The fee runs $300 to $1,500 for a residential assessment.

The engineer's report also matters for any insurance or disclosure claim downstream. "The contractor said it was fine" doesn't carry the weight of an engineer's stamped report. For cosmetic damage on non-structural trim, a competent carpenter handles it. For anything carrying load, hire the engineer first.

5 maintenance habits handle most of it. Annual pro inspection in regions with termite pressure. Moisture management around the foundation (gutter extensions, regrading low spots, no chronic damp soil against siding). No wood-to-soil contact (gap any wood members above grade with concrete or treated material). Sealed exterior wood (paint or stain refreshed before bare wood is exposed). Screened vents and weep holes (1/4 inch hardware cloth or pre-formed inserts).

Those 5 block roughly 90% of future activity. The annual inspection is the highest-leverage single habit because it catches new activity at year 1 rather than year 7, which compresses the eventual repair from 5 figures to 3.